Certain electrical systems require that conductive wire be formed into a predetermined pattern and be adhered to a backing material or substrate for support or for other purposes. Successive portions of the wire typically extend in parallel, spaced apart relationship although other wire configurations may be needed in some instances.
As a specific example, apparatus for studying heat transfer through building wall materials may include a wire array formed of a conductor such as nickel which has an electrical resisivity that varies as a function of temperature. The array is disposed against the wall material and functions electrically as a component of a bridge circuit for detecting heat. Wire arrays of this general type may also be used in other apparatus such as in strain gages or antennas among other examples.
Fabrication of wire arrays has heretofore been undesirably complicated and costly, particularly if the wire must have a precise predetermined configuration. Fixtures, winding frames and the like as heretofore designed for the purpose tend to be bulky, complex and expensive. Many such devices are limited to the forming of wire arrays or grids of the particular type having a series of separate lengths of wire disposed in parallel relationship. Some usages, such as the above discussed apparatus for studying heat transfer in wall materials, require that at least sizable portions of the array be formed with a continuous wire.
Other known fixtures provide spaced apart rows of pins between which a continuous wire can be wound to form an array but do not enable the portions of the wire in the vicinity of the pins to be adhered to the backing material.
Many prior techniques and devices for forming a continuous wire into an array tend to introduce some degree of tension into the wire. This can be highly undesirable in certain usages of which the above mentioned apparatus for studying thermal characteristics of wall materials is again an example. Such tension can alter the electrical parameters of the wire in a manner which detracts from the accuracy of the measurement. In such applications it would be desirable to provide for a slight controlled amount of slack in the wire as it is adhered to the backing material.
Some prior fabrication procedures require that openings be formed in the backing material or substrate to receive pins or the like around which the wire is strung. Openings or other deformations of the backing material are also undesirable in certain usages of wire arrays such as in the specific usage discussed above.
The present invention is directed to overcoming one or more of the problems discussed above.